Locher lists Violon with the following description: Dr. Faisst advises that in case the very incisive 8-ft. Violoncello should not suit the quality of the general tone, a wider-sized and rather more powerfully intonated Violoncello, of a clear, sound, and only moderately stringy tone, should be used. He then calls it 8-ft. Violon, in contradistinction to the proper 8-ft. Violoncello. The name Violon often occurs in Northern Germany for a similar 8-ft. stop, and I have now and again proposed it for Swiss organs. Grove concurs with Williams's description, which reads: I Spanish stopped pipes on pedal or manual; the normal Spanish term for �stopped�, Gedackt, etc., as in Flautado Violón (Bourdon). II A German open pedal stop of medium volume and nondescript tone, found more especially in the 18th cent. Scaling was generally narrow, the wood or metal pipes being a substitute for the more expensive Prinzipal 16'; but conical at Ulm Minster (c. 1700), as was Hildebrandt's unusual 8' Violon at Naumburg, 1743-6. The tone was sometimes strong (J. Wagner), sometimes not (M. Engler). The name Violón has also been listed as a Spanish synonym for Stopped Diapason. In France, Violon is a synonym for Violin, and it has also been used as a synonym for Violone.
Osiris lists over 250 examples, the majority being at 8' or 16', with three at 4', and one at 32'.